This section contains an alphabetic list of the line device functions, phone device functions, and assisted telephony functions in the Telephony Application Programming Interface (TAPI). For a categorization of TAPI functions by service level and task, see TAPI Quick Function Reference.
The information for each function includes a list of the valid call states on entry of the function and typical call state transitions when the request is complete. The actual states in which a function can be performed can be further limited by the capabilities of the service provider. Applications must check the dwCallFeatures member in the LINECALLSTATUS structure, the dwAddressFeatures member in the LINEADDRESSSTATUS structure, and the dwLineFeatures member in the LINEDEVSTATUS structure to determine whether or not a function is permitted within the current call state.